Featured Research

from universities, journals, and other organizations

Scientist uncovers switch controlling protein production

Date:

December 23, 2010

Source:

Scripps Research Institute

Summary:

Scientist have discovered a molecular switch that controls the synthesis of ribosomes. Ribosomes are the large machineries inside all living cells that produce proteins, the basic working units of any cell. These new findings offer a novel target for potential treatments for a range of diseases, including cancer.

Share This

A scientist from the Florida campus of The Scripps Research Institute has discovered a molecular switch that controls the synthesis of ribosomes. Ribosomes are the large machineries inside all living cells that produce proteins, the basic working units of any cell. These new findings offer a novel target for potential treatments for a range of diseases, including cancer.

Related Articles

The study is published in the December 24, 2010 edition of the Journal of Molecular Biology.

The study identified the molecular switch, essentially formed by a small sequence of RNA, that controls a critical part of ribosome synthesis to allow for strict, albeit temporary, regulation of the process.

"These kinds of switches in RNA are thought to be slow acting," said Katrin Karbstein, an assistant professor in the Department of Cancer Biology at Scripps Florida who helped lead the study. "That suggests a point where we might intervene to modify the process -- then you could potentially shut down the pathway, because if you don't produce ribosomes, you cannot make proteins. Thus, cells can't grow. That would be a desirable outcome in cancer, for example."

This slowness may be there precisely so these regulatory points can be introduced for cells to downregulate growth when nutrition is scarce.

"Perhaps, nature has found a way to exploit RNA's Achilles' heel -- its propensity to form alternative structures that can lead to protein misfolding, which, in turn, can cause diseases ranging from Alzheimer's to diabetes," Karbstein said. "Nature might be using this to stall important biological processes and allow for quality control and regulation."

The synthesis of proteins involves ribosomes, large macromolecular machines required for cell growth in all organisms. Ribosomes read the genetic code carried by messenger RNA and then catalyze or translate that RNA code into proteins within cells, assembling them from amino acids.

To produce mature ribosomal RNAs (rRNAs), the catalysts that control protein synthesis in all cells, the body first needs perfectly formed intermediate or pre rRNAs, which can be further processed into fully functioning ones. The intermediate form is produced as an RNA transcript that is cleaved or cut in multiple steps to produce mature rRNA.

"While we believe that this switch is essential for ribosome assembly, it seems unlikely that this is the only event that regulates cleavage," Karbstein said. "However, tight regulation of ribosome synthesis is essential to ensure the structural integrity of mature ribosomes."

Cutting Extra Material

The ribosomal RNA that is transcribed has extra material in it, Karbstein said, so it is necessary to cut it down -- that's why these cuts or cleavages are so essential to the process of producing the final rRNA product.

The study also suggests RNA itself exploits its own natural ability to form these stable structural switches to order and regulate various RNA-dependent biological processes.

"What is interesting," Karbstein said, "is that as the organism becomes more complex, the number of cleavages needed increases. This may make the process more accurate and that may be an evolutionary advantage, but even in bacteria this cutting is not done in a simple way. We still don't know exactly why that is."

Perhaps these strictly ordered cleavage steps are introduced to produce singularly perfect intermediates, she added. This is important because cleavage is an irreversible energy-releasing process with the potential to shift the landscape of assembly towards the final product. As a result, cleavage steps should be carefully controlled and should only occur if the assembly intermediate is correct.

"Ribosomes make mistakes rarely, on the order of one in 10,000 amino acid changes," Karbstein said. "A lot of this accuracy depends on conversations between different parts of the ribosomes, so if the structure of the RNA isn't correct, these conversations can't happen. And that means more mistakes, and that's not good because it can lead to any number of disease states."

For now, Karbstein said she's interested in looking at small molecules that perturb the switch, and finding out if this affects the quality of the ribosomes produced.

"Certain kinds of antibiotics work by making the ribosomes produce more mistakes -- it's not a huge increase but it's enough to make these cells die," she said. "Maybe we can find molecules that similarly lead to the production of 'worse' ribosomes."

More From ScienceDaily

More Plants & Animals News

Featured Research

Mar. 3, 2015 — While studying a ground-nesting bird population near El Reno, Okla., a research team found that stress during a severe weather outbreak of May 31, 2013, had manifested itself into malformations in ... full story

Mar. 3, 2015 — The 3-D printing scene, a growing favorite of do-it-yourselfers, has spread to the study of plasma physics. With a series of experiments, researchers have found that 3-D printers can be an important ... full story

Mar. 3, 2015 — Most people consume more salt than they need and therefore have a higher risk of heart disease and stroke, which are the two leading causes of death worldwide. But a new study reveals that dietary ... full story

Mar. 3, 2015 — By examining the forces that the segments of mosquito legs generate against a water surface, researchers have unraveled the mechanical logic that allows the mosquitoes to walk on water, which may ... full story

Mar. 3, 2015 — Pediatric otolaryngologists and surgeons are concerned with parents getting the wrong message regarding the safety/desirability of letting babies and young children eat peanuts to prevent them from ... full story

Mar. 3, 2015 — Researchers have developed a new way of rapidly screening yeasts that could help produce more sustainable biofuels. The new technique could also be a boon in the search for new ways of deriving ... full story

Mar. 3, 2015 — Similar to humans and animals, plants possess an innate immune system that protects them from invading pathogens. Molecular structures that only occur in pathogens enable their recognition and ... full story

Mar. 3, 2015 — For almost a century, scientists have been puzzled by a process that is crucial to much of the life in Earth's oceans: Why does calcium carbonate, the tough material of seashells and corals, ... full story

Mar. 3, 2015 — To simulate chimp behavior, scientists created a computer model based on equations normally used to describe the movement of atoms and molecules in a confined space. An interdisciplinary research ... full story

Featured Videos

Rare Goblin Shark Found in Australia

AFP (Mar. 3, 2015) — A goblin shark, a rare sea creature described as an &apos;alien of the deep&apos; is found off Australia and delivered to the Australian Museum in Sydney. Duration: 01:25
Video provided by AFP

Zookeepers Copy Animal Poses In Hilarious Viral Photos

Buzz60 (Mar. 2, 2015) — Zookeepers at the Symbio Wildlife Park in Helensburgh, Australia decided to take some of their favorite animal photos and recreate them by posing just like the animals. Jen Markham (@jenmarkham) has the story.
Video provided by Buzz60

Related Stories

June 23, 2014 — The 'missing link' in the chemical system that enables animal cells to produce ribosomes -- the thousands of protein 'factories' contained within each cell that manufacture all of ... full story

Oct. 15, 2013 — When cells grow and proliferate, they need to produce large amounts of protein. All this protein is made by ribosomes, therefore rapid growth requires many ribosomes. Because ribosomes are expensive ... full story

June 29, 2013 — Synthetic biology researchers have for the first time synthesized ribosomes from scratch in a test tube. The researchers took an approach different from their predecessors: they mimicked the natural ... full story

May 4, 2011 — Scientists have discovered a new component of mitochondria that plays a key part in their function. The discovery is of potential significance to our understanding of both inherited and age-related ... full story

Mar. 30, 2010 — The organelles of photosynthesis -- the chloroplasts -- have their own DNA, messenger RNA and ribosomes for forming proteins. Scientists have now discovered how to regulate the formation of proteins ... full story

ScienceDaily features breaking news and videos about the latest discoveries in health, technology, the environment, and more -- from major news services and leading universities, scientific journals, and research organizations.